RNA variant assessment using transactivation and transdifferentiation.

Understanding the impact of splicing and nonsense variants on RNA is crucial for the resolution of variant classification as well as their suitability for precision medicine interventions. This is primarily enabled through RNA studies involving transcriptomics followed by targeted assays using RNA isolated from clinically accessible tissues (CATs) such as blood or skin of affected individuals. Insufficient disease gene expression in CATs does however pose a major barrier to RNA based investigations, which we show is relevant to 1,436 Mendelian disease genes. We term these "silent" Mendelian genes (SMGs), the largest portion (36%) of which are associated with neurological disorders. We developed two approaches to induce SMG expression in human dermal fibroblasts (HDFs) to overcome this limitation, including CRISPR-activation-based gene transactivation and fibroblast-to-neuron transdifferentiation. Initial transactivation screens involving 40 SMGs stimulated our development of a highly multiplexed transactivation system culminating in the 6- to 90,000-fold induction of expression of 20/20 (100%) SMGs tested in HDFs. Transdifferentiation of HDFs directly to neurons led to expression of 193/516 (37.4%) of SMGs implicated in neurological disease. The magnitude and isoform diversity of SMG expression following either transactivation or transdifferentiation was comparable to clinically relevant tissues. We apply transdifferentiation and/or gene transactivation combined with short- and long-read RNA sequencing to investigate the impact that variants in USH2A, SCN1A, DMD, and PAK3 have on RNA using HDFs derived from affected individuals. Transactivation and transdifferentiation represent rapid, scalable functional genomic solutions to investigate variants impacting SMGs in the patient cell and genomic context.

Solving the Etiology of Developmental and Epileptic Encephalopathy with Spike-Wave Activation in Sleep (D/EE-SWAS).

OBJECTIVE: To understand the etiological landscape and phenotypic differences between 2 developmental and epileptic encephalopathy (DEE) syndromes: DEE with spike-wave activation in sleep (DEE-SWAS) and epileptic encephalopathy with spike-wave activation in sleep (EE-SWAS). METHODS: All patients fulfilled International League Against Epilepsy (ILAE) DEE-SWAS or EE-SWAS criteria with a Core cohort (n = 91) drawn from our Epilepsy Genetics research program, together with 10 etiologically solved patients referred by collaborators in the Expanded cohort (n = 101). Detailed phenotyping and analysis of molecular genetic results were performed. We compared the phenotypic features of individuals with DEE-SWAS and EE-SWAS. Brain-specific gene co-expression analysis was performed for D/EE-SWAS genes. RESULTS: We identified the etiology in 42/91 (46%) patients in our Core cohort, including 29/44 (66%) with DEE-SWAS and 13/47 (28%) with EE-SWAS. A genetic etiology was identified in 31/91 (34%). D/EE-SWAS genes were highly co-expressed in brain, highlighting the importance of channelopathies and transcriptional regulators. Structural etiologies were found in 12/91 (13%) individuals. We identified 10 novel D/EE-SWAS genes with a range of functions: ATP1A2, CACNA1A, FOXP1, GRIN1, KCNMA1, KCNQ3, PPFIA3, PUF60, SETD1B, and ZBTB18, and 2 novel copy number variants, 17p11.2 duplication and 5q22 deletion. Although developmental regression patterns were similar in both syndromes, DEE-SWAS was associated with a longer duration of epilepsy and poorer intellectual outcome than EE-SWAS. INTERPRETATION: DEE-SWAS and EE-SWAS have highly heterogeneous genetic and structural etiologies. Phenotypic analysis highlights valuable clinical differences between DEE-SWAS and EE-SWAS which inform clinical care and prognostic counseling. Our etiological findings pave the way for the development of precision therapies. ANN NEUROL 2024;96:932-943.

Unraveling the molecular interactions between α7 nicotinic receptor and a RIC3 variant associated with backward speech.

Recent work putatively linked a rare genetic variant of the chaperone Resistant to Inhibitors of acetylcholinesterase (RIC3) (NM_024557.4:c.262G > A, NP_078833.3:p.G88R) to a unique ability to speak backwards, a language skill that is associated with exceptional working memory capacity. RIC3 is important for the folding, maturation, and functional expression of α7 nicotinic acetylcholine receptors (nAChR). We compared and contrasted the effects of RIC3G88R on assembly, cell surface expression, and function of human α7 receptors using fluorescent protein tagged α7 nAChR and Förster resonance energy transfer (FRET) microscopy imaging in combination with functional assays and 125I-α-bungarotoxin binding. As expected, the wild-type RIC3 protein was found to increase both cell surface and functional expression of α7 receptors. In contrast, the variant form of RIC3 decreased both. FRET analysis showed that RICG88R increased the interactions between RIC3 and α7 protein in the endoplasmic reticulum. These results provide interesting and novel data to show that a RIC3 variant alters the interaction of RIC3 and α7, which translates to decreased cell surface and functional expression of α7 nAChR.

Deleterious variants in CRLS1 lead to cardiolipin deficiency and cause an autosomal recessive multi-system mitochondrial disease.

Mitochondrial diseases are a group of inherited diseases with highly varied and complex clinical presentations. Here, we report four individuals, including two siblings, affected by a progressive mitochondrial encephalopathy with biallelic variants in the cardiolipin biosynthesis gene CRLS1. Three affected individuals had a similar infantile presentation comprising progressive encephalopathy, bull's eye maculopathy, auditory neuropathy, diabetes insipidus, autonomic instability, cardiac defects and early death. The fourth affected individual presented with chronic encephalopathy with neurodevelopmental regression, congenital nystagmus with decreased vision, sensorineural hearing loss, failure to thrive and acquired microcephaly. Using patient-derived fibroblasts, we characterized cardiolipin synthase 1 (CRLS1) dysfunction that impaired mitochondrial morphology and biogenesis, providing functional evidence that the CRLS1 variants cause mitochondrial disease. Lipid profiling in fibroblasts from two patients further confirmed the functional defect demonstrating reduced cardiolipin levels, altered acyl-chain composition and significantly increased levels of phosphatidylglycerol, the substrate of CRLS1. Proteomic profiling of patient cells and mouse Crls1 knockout cell lines identified both endoplasmic reticular and mitochondrial stress responses, and key features that distinguish between varying degrees of cardiolipin insufficiency. These findings support that deleterious variants in CRLS1 cause an autosomal recessive mitochondrial disease, presenting as a severe encephalopathy with multi-systemic involvement. Furthermore, we identify key signatures in cardiolipin and proteome profiles across various degrees of cardiolipin loss, facilitating the use of omics technologies to guide future diagnosis of mitochondrial diseases.

Bi-allelic variants in SPATA5L1 lead to intellectual disability, spastic-dystonic cerebral palsy, epilepsy, and hearing loss.

Spermatogenesis-associated 5 like 1 (SPATA5L1) represents an orphan gene encoding a protein of unknown function. We report 28 bi-allelic variants in SPATA5L1 associated with sensorineural hearing loss in 47 individuals from 28 (26 unrelated) families. In addition, 25/47 affected individuals (53%) presented with microcephaly, developmental delay/intellectual disability, cerebral palsy, and/or epilepsy. Modeling indicated damaging effect of variants on the protein, largely via destabilizing effects on protein domains. Brain imaging revealed diminished cerebral volume, thin corpus callosum, and periventricular leukomalacia, and quantitative volumetry demonstrated significantly diminished white matter volumes in several individuals. Immunofluorescent imaging in rat hippocampal neurons revealed localization of Spata5l1 in neuronal and glial cell nuclei and more prominent expression in neurons. In the rodent inner ear, Spata5l1 is expressed in the neurosensory hair cells and inner ear supporting cells. Transcriptomic analysis performed with fibroblasts from affected individuals was able to distinguish affected from controls by principal components. Analysis of differentially expressed genes and networks suggested a role for SPATA5L1 in cell surface adhesion receptor function, intracellular focal adhesions, and DNA replication and mitosis. Collectively, our results indicate that bi-allelic SPATA5L1 variants lead to a human disease characterized by sensorineural hearing loss (SNHL) with or without a nonprogressive mixed neurodevelopmental phenotype.

Genetic aetiologies for childhood speech disorder: novel pathways co-expressed during brain development.

Childhood apraxia of speech (CAS), the prototypic severe childhood speech disorder, is characterized by motor programming and planning deficits. Genetic factors make substantive contributions to CAS aetiology, with a monogenic pathogenic variant identified in a third of cases, implicating around 20 single genes to date. Here we aimed to identify molecular causation in 70 unrelated probands ascertained with CAS. We performed trio genome sequencing. Our bioinformatic analysis examined single nucleotide, indel, copy number, structural and short tandem repeat variants. We prioritised appropriate variants arising de novo or inherited that were expected to be damaging based on in silico predictions. We identified high confidence variants in 18/70 (26%) probands, almost doubling the current number of candidate genes for CAS. Three of the 18 variants affected SETBP1, SETD1A and DDX3X, thus confirming their roles in CAS, while the remaining 15 occurred in genes not previously associated with this disorder. Fifteen variants arose de novo and three were inherited. We provide further novel insights into the biology of child speech disorder, highlighting the roles of chromatin organization and gene regulation in CAS, and confirm that genes involved in CAS are co-expressed during brain development. Our findings confirm a diagnostic yield comparable to, or even higher, than other neurodevelopmental disorders with substantial de novo variant burden. Data also support the increasingly recognised overlaps between genes conferring risk for a range of neurodevelopmental disorders. Understanding the aetiological basis of CAS is critical to end the diagnostic odyssey and ensure affected individuals are poised for precision medicine trials.

The diagnostic yield of genetic and metabolic investigations in syndromic and nonsyndromic patients with autism spectrum disorder, global developmental delay, or intellectual disability from a dedicated neurodevelopmental disorders genetics clinic.

First-tier genetic investigations for patients with neurodevelopmental disorders (NDDs) may include chromosomal microarray, Fragile X testing, and screening for inherited metabolic diseases, but most remain undiagnosed upon completion of testing. Here, we report the diagnostic yields of genetic testing for 537 patients with at least one of autism spectrum disorder, global developmental delay, and/or intellectual disability. Patients were assessed in a single neurodevelopmental genetics clinic, and each underwent a standardized history and physical examination. Each patient was characterized as syndromic or nonsyndromic based on clinical features. Our results demonstrate that multigene sequencing (with an NDD gene panel or exome) had a higher diagnostic yield (8%; 95% confidence interval [CI]: 5%, 13%) than chromosomal microarray and Fragile X testing combined (4%; 95% CI: 3%, 7%). Biochemical screening for inherited metabolic diseases had a diagnostic yield of zero. The diagnostic yield of genetic testing was significantly higher for syndromic patients than for nonsyndromic patients (odds ratio [OR] 3.09; 95% CI: 1.46, 6.83) and higher for female patients than for male (OR 3.21; 95% CI: 1.52, 6.82). These results add to the growing evidence supporting a comprehensive genetic evaluation that includes both copy number analysis and sequencing of known NDD genes for patients with NDDs.

Does Celecoxib Prescription for Pain Management Affect Post-tonsillectomy Hemorrhage Requiring Surgery? A Retrospective Observational Cohort Study.

BACKGROUND: Adenotonsillectomy and tonsillectomy (referred to as tonsillectomy hereafter) are common pediatric surgeries. Postoperative complications include hemorrhage requiring surgery (2 to 3% of cases) and pain. Although nonsteroidal anti-inflammatory drugs are commonly administered for postsurgical pain, controversy exists regarding bleeding risk with cyclooxygenase-1 inhibition and associated platelet dysfunction. Preliminary evidence suggests selective cyclooxygenase-2 inhibitors, for example celecoxib, effectively manage pain without adverse events including bleeding. Given the paucity of data for routine celecoxib use after tonsillectomy, this study was designed to investigate the association between postoperative celecoxib prescription and post-tonsillectomy hemorrhage requiring surgery using chart-review data from the Children's Hospital of Eastern Ontario. METHODS: After ethics approval, a retrospective single-center observational cohort study was performed in children less than 18 yr of age undergoing tonsillectomy from January 2007 to December 2017. Cases of adenoidectomy alone were excluded due to low bleed rates. The primary outcome was the proportion of patients with post-tonsillectomy hemorrhage requiring surgery. The association between a celecoxib prescription and post-tonsillectomy hemorrhage requiring surgery was estimated using inverse probability of treatment weighting based on propensity scores and using generalized estimating equations to accommodate clustering by surgeon. RESULTS: An initial patient cohort of 6,468 was identified, and 5,846 children with complete data were included in analyses. Median (interquartile range) age was 6.10 (4.40, 9.00) yr, and 46% were female. In the cohort, 28.1% (n = 1,644) were prescribed celecoxib. Among the 4,996 tonsillectomy patients, 1.7% (n = 86) experienced post-tonsillectomy hemorrhage requiring surgery. The proportion with post-tonsillectomy hemorrhage requiring surgery among patients who had a tonsillectomy and were or were not prescribed celecoxib was 1.94% (30 of 1,548; 95% CI, 1.36 to 2.75) and 1.62% (56 of 3,448; 95% CI, 1.25 to 2.10), respectively. Modeling did not identify an association between celecoxib prescription and increased odds of post-tonsillectomy hemorrhage requiring surgery (odds ratio = 1.4; 95% CI, 0.85 to 2.31; P = 0.20). CONCLUSIONS: Celecoxib does not significantly increase the odds of post-tonsillectomy hemorrhage requiring surgery, after adjusting for covariates. This large pediatric cohort study of celecoxib administered after tonsillectomy provides compelling evidence for safety but requires confirmation with a multisite randomized controlled trial.

Mathematics skills in children with genetic generalized epilepsy: Cognitive and clinical correlates. Preliminary results.

Impairments in mathematics have been found in children with Genetic Generalized Epilepsy (GGE), yet little is known about the underpinnings of these difficulties. The aim of this study was to investigate basic numeracy and secondary mathematics skills in GGE and explore cognitive and clinical correlates that relate to those skills. Nineteen children with GGE and 22 typically developing controls aged 8-16 years completed a neuropsychological battery which assessed: (i) basic numeracy skills: non-symbolic and symbolic magnitude comparison; (ii) secondary mathematics skills: calculation, reasoning, and fluency; and (iii) cognitive skills: intelligence, fluid reasoning, processing speed, and working memory. Epilepsy clinical factors (age of epilepsy onset, duration of epilepsy, number of anti-seizure medications) were also recorded. Children with GGE were impaired in select basic numeracy skills (non-symbolic magnitude comparison), and all secondary mathematics skills compared to controls. In children with GGE, the visuo-spatial central executive correlated with both basic numeracy skills. The verbal central executive correlated with mathematics reasoning. Non-verbal intelligence was related to symbolic magnitude comparison and mathematics reasoning. Fluid reasoning was correlated with non-symbolic magnitude comparison and mathematics problems solving. Epilepsy variables did not relate to mathematics outcomes. Overall, we found that children with GGE experience significant difficulties in select basic numeracy and all secondary mathematics skills. Risk factors for mathematics difficulties included reduced working memory capacity, lower intelligence and fluid reasoning. Our findings suggest that children with GGE may require accommodation for limited central executive working memory capacity in combination with academic supports for poor mathematics skills.

Does E-learning Facilitate Medical Education in Pediatric Neurology?

BACKGROUND: E-learning has become commonplace in medical education. Incorporation of multimedia, clinical cases, and interactive elements has increased its attractiveness over textbooks. Although there has been an expansion of e-learning in medicine, the feasibility of e-learning in pediatric neurology is unclear. This study evaluates knowledge acquisition and satisfaction using pediatric neurology e-learning compared to conventional learning. METHODS: Residents of Canadian pediatrics, neurology, and pediatric neurology programs and medical students from Queens University, Western University, and the University of Ottawa were invited to participate. Learners were randomly assigned two review papers and two ebrain modules in a four-topic crossover design. Participants completed pre-tests, experience surveys, and post-tests. We calculated the median change in score from pre-test to post-test and constructed a mixed-effects model to determine the effect of variables on post-test scores. RESULTS: In total, 119 individuals participated (53 medical students; 66 residents). Ebrain had a larger positive change than review papers in post-test score from pre-test score for the pediatric stroke learning topic but a smaller positive change for Duchenne muscular dystrophy, childhood absence epilepsy, and acute disseminated encephalomyelitis. Learning topics showed statistical relationship to post-test scores (p = 0.04). Depending on topic, 57-92% (N = 59-66) of respondents favored e-learning over review article learning. CONCLUSIONS: Ebrain users scored higher on post-tests than review paper users. However, the effect is small and it is unclear if it is educationally meaningful. Although the difference in scores may not be substantially different, most learners preferred e-learning. Future projects should focus on improving the quality and efficacy of e-learning modules.

Influence of hybrid class and ensiling duration on deoxynivalenol accumulation and its derivative deoxynivalenol-3-glucoside while ensiling corn for silage.

In silage corn (Zea mays L.), Fusarium graminearum causes diseases and produces the mycotoxin deoxynivalenol (DON). The work presented here investigated DON accumulation and its fate during the ensiling of ground, whole-plant material obtained from dual-purpose (DP) and brown midrib (BMR) corn hybrids. Multi-year field trials arranged in a randomized complete block design were conducted in Wisconsin to evaluate BMR and DP corn hybrids in response to fungicide treatment. At harvest, the samples were chopped and vacuum sealed for a mini-silo time series assessment with silos opened following anaerobic fermentation for 0, 30, 60, 90 and 120 days. Repeated measures analysis of ensiled corn showed that hybrid (P < 0.01) and ensiling duration (P < 0.01) significantly impacted DON concentration through ensiling, while fungicide treatment had no significant effect (P > 0.05). Across hybrids and treatments, DON concentrations detected at harvest were the lowest with DON3G at harvest significantly (P < 0.01) and highly correlated (r = 0.74) with DON concentration 30-days post ensiling. These findings suggest that mycotoxin testing in corn should include not only DON but also for conjugates of DON that can be metabolized back to DON and increase the final DON concentration during ensiling.

Tone management: An environmental scan of current management practices across Canada.

BACKGROUND: Currently, there are no standardized approaches to care or evaluation for tone dysfunction in Canada. The study authors hypothesize that there is significant practice variation across the country. This environmental scan is aimed to describe the current practice for management of paediatric patients with hypertonia across Canada. METHODS: A web-based survey was developed by the authors with a multi-disciplinary approach and sent to representative paediatric rehabilitation sites in each province in Canada. Disciplines at the rehabilitation sites surveyed included all or some of the following disciplines: physiatry, neurology, neurosurgery, plastic surgery, orthopaedic surgery, physiotherapy and occupational therapy. All statistical analyses were performed using the R statistical software version 4.0. Fifteen rehabilitation sites were contacted, and 12 sites were used for the final analysis. RESULTS: Cerebral palsy was found to be the most common diagnosis for tone dysfunction, with 58% of sites diagnosing greater than 20 new patients per year. In 67% of sites, patients were seen within a formal multidisciplinary clinic to manage hypertonia. All 12 sites utilized oral baclofen and gabapentin, and 92% of sites utilized trihexyphenidyl. Botulinum toxin injections were offered at 50% of sites. Upper and lower extremity surgical procedures were offered in 83% of the sites. CONCLUSION: The information gained from this study provides some insight into the current practice across Canada for children with hypertonia. This study may assist in the development of a national, standardized strategy to tone management, potentially facilitating more equitable access to care for patients.

Investigating the Risk Factors Associated With Acute Neurologic Dysfunction in Pediatric Hyperglycemic Emergencies on Transport.

OBJECTIVE: This study aims to identify key characteristics of hyperglycemic emergencies in pediatric patients and those at risk for acute neurologic dysfunction during transport. METHODS: We conducted a retrospective chart review of pediatric patients during interfacility transport by Ornge, Ontario's critical care transport service, from January 1, 2009, to December 31, 2019. Data were extracted from electronic patient care records and included demographic, clinical, and transport-specific variables. Two multiple logistic regression models were utilized to analyze associations between predictor variables and neurologic dysfunction (GCS, <14). RESULTS: Of the 399 patients included, 24% (n = 95) had a GCS score of <14. Patients with a GCS score of <14 were more acidotic compared with those with a GCS score of ≥14 (median pH, 6.9 [IQR, 6.8-7.1] vs median, pH 7.0 [IQR, 1.0-7.2]; P < 0.001). Higher median corrected sodium for glucose values were observed in patients with a GCS score of <14 compared to those with a GCS score of ≥14 (145.7 mmol/L [IQR, 140.6-149.9 mmol/L] vs 141.7 mmol/L [IQR, 138.3-146.4 mmol/L]; P < 0.001). Multiple logistic regression identified younger age (aOR, 0.91; 95% CI, 0.84-0.98; P = 0.01), severe acidosis (pH <7.10; aOR, 3.56; 95% CI, 1.33-11.62; P = 0.02), and higher creatinine (aOR, 1.01; 95% CI, 1.01-1.02; P < 0.001) as risk factors for acute neurologic dysfunction. CONCLUSIONS: Our findings reveal associations between acute neurologic dysfunction, younger age, severe acidosis, and elevated corrected sodium for glucose values in pediatric hyperglycemic emergencies during transport. Education and adherence to guidelines are recommended to improve outcomes in this population.

Tetrakis(N-heterocyclic Carbene)-Diboron(0): Double Single-Electron-Transfer Reactivity.

The use of 1,3,4,5-tetramethylimidazol-2-ylidene (IMe) to coordinate with diatomic B2 species afforded a tetrakis(N-heterocyclic carbene)-diboron(0) [(IMe)2B-B(IMe)2] (2). The singly bonded B2 moiety therein possesses a valence electronic configuration 1σg21πu21πg*2 with four vacant molecular orbitals (1σu*, 2σg, 1πu', 1πg'*) coordinated with IMe. Its unprecedented electronic structure is analogous to the energetically unfavorable planar hydrazine with a D2h symmetry. The two highly reactive πg* antibonding electrons enable double single-electron-transfer (SET) reactivity in small-molecule activation. Compound 2 underwent a double SET reduction with CO2 to form two carbon dioxide radical anions CO2•-, which then reduced pyridine to yield a carboxylated pyridine reductive coupling dianion [O2CNC5(H)5-C5(H)5NCO2]2- and converted compound 2 to the tetrakis(N-heterocyclic carbene)-diborene dication [(IMe)2B═B(IMe)2]2+ (32+). This is a remarkable transition-metal-free SET reduction of CO2 without ultraviolet/visible (UV/vis) light conditions.

Non-Fullerene Electron Acceptors Based on Hybridisation of Corannulene and Thiophene-S,S-Dioxide Motifs.

Herein we show that hybridisation of buckybowl corannulene and thiophene-S,S-dioxide motifs is a general approach for the preparation of high electron affinity molecular materials. The devised synthesis is modular and relies on thienannulation of corannnulene-based phenylacetylene scaffolds. The final compounds are highly soluble in common organic solvents. These compounds also exhibit interesting optical properties such as absorption and emission in the blue/green regions of the electromagnetic spectrum. Importantly, a bis-S,S-dioxide derivative exhibits three reversible reductions similar in their strength to the prevalent fullerene-based electron acceptor phenyl-C61 -butyric acid methyl ester (PC61 BM).

Monoallelic and biallelic mutations in RELN underlie a graded series of neurodevelopmental disorders.

Reelin, a large extracellular protein, plays several critical roles in brain development and function. It is encoded by RELN, first identified as the gene disrupted in the reeler mouse, a classic neurological mutant exhibiting ataxia, tremors and a 'reeling' gait. In humans, biallelic variants in RELN have been associated with a recessive lissencephaly variant with cerebellar hypoplasia, which matches well with the homozygous mouse mutant that has abnormal cortical structure, small hippocampi and severe cerebellar hypoplasia. Despite the large size of the gene, only 11 individuals with RELN-related lissencephaly with cerebellar hypoplasia from six families have previously been reported. Heterozygous carriers in these families were briefly reported as unaffected, although putative loss-of-function variants are practically absent in the population (probability of loss of function intolerance = 1). Here we present data on seven individuals from four families with biallelic and 13 individuals from seven families with monoallelic (heterozygous) variants of RELN and frontotemporal or temporal-predominant lissencephaly variant. Some individuals with monoallelic variants have moderate frontotemporal lissencephaly, but with normal cerebellar structure and intellectual disability with severe behavioural dysfunction. However, one adult had abnormal MRI with normal intelligence and neurological profile. Thorough literature analysis supports a causal role for monoallelic RELN variants in four seemingly distinct phenotypes including frontotemporal lissencephaly, epilepsy, autism and probably schizophrenia. Notably, we observed a significantly higher proportion of loss-of-function variants in the biallelic compared to the monoallelic cohort, where the variant spectrum included missense and splice-site variants. We assessed the impact of two canonical splice-site variants observed as biallelic or monoallelic variants in individuals with moderately affected or normal cerebellum and demonstrated exon skipping causing in-frame loss of 46 or 52 amino acids in the central RELN domain. Previously reported functional studies demonstrated severe reduction in overall RELN secretion caused by heterozygous missense variants p.Cys539Arg and p.Arg3207Cys associated with lissencephaly suggesting a dominant-negative effect. We conclude that biallelic variants resulting in complete absence of RELN expression are associated with a consistent and severe phenotype that includes cerebellar hypoplasia. However, reduced expression of RELN remains sufficient to maintain nearly normal cerebellar structure. Monoallelic variants are associated with incomplete penetrance and variable expressivity even within the same family and may have dominant-negative effects. Reduced RELN secretion in heterozygous individuals affects only cortical structure whereas the cerebellum remains intact. Our data expand the spectrum of RELN-related neurodevelopmental disorders ranging from lethal brain malformations to adult phenotypes with normal brain imaging.

Normative values of renin and aldosterone in clinically stable preterm neonates.

BACKGROUND: There is a paucity of literature on the normative levels of plasma renin concentration (PRC) and serum aldosterone (SA) in premature neonates. This study aims to provide normative data on PRC and SA levels in preterm neonates in the first 2 weeks after birth and explore associations with maternal, perinatal, or postnatal factors. METHODS: Neonates born at 26- to 34-week gestation were recruited from two neonatal intensive care units in Canada and Australia. The direct renin assay PRC and SA were analyzed on day 1 and days 14-21 after birth to compare across categorical variables and to produce normative values. RESULTS: A total of 262 subjects were enrolled from the Canadian (29%) and Australian (71%) sites. The mean gestational age was 30 weeks, with a mean birth weight of 1457 g. The normative values of PRC and SA for neonates born between 26 + 0 and 29 + 6 weeks and 30 + 0 and 34 + 0 weeks of gestation were produced for day 1 and day 14-21 after birth. Both PRC and SA increased from day 1 to day 14-21. The more premature neonates reached a higher PRC on days 14-21 after birth but exhibited lower SA levels on day 1 after birth. When comparing gender, birth weight, and maternal risk factor categories, no statistical differences in PRC or SA were found. A small but significant decrease in PRC, but not SA, was noted for neonates with placental pathology. CONCLUSIONS: This study produced normative values of PRA and SA in clinically stable preterm neonates that can be referenced for use in clinical practice. A higher resolution version of the Graphical abstract is available as Supplementary information.

Urgent computed tomography angiography in paediatric stroke.

AIM: To improve delivery of acute therapies for acute ischaemic stroke (AIS). METHOD: We identified factors influencing the speed of diagnosis and delivery of acute therapies in a prospective cohort of 21 children with suspected AIS (eight with AIS, 13 stroke mimics) and explored them in a retrospective cohort with confirmed AIS. RESULTS: Approximately half of the prospective and total AIS cohorts presented with acute, sustained hemiparesis, and were diagnosed relatively quickly. AIS was suspected and diagnosed more slowly in the half presenting with symptoms other than sustained hemiparesis. Thirty-one out of 51 patients with AIS (19 females, 32 males, mean age 8 years 6 months, SD 5 years 4 months) had arterial abnormalities identified by computed tomography angiography (CTA) or magnetic resonance angiography (MRA): 11 with large vessel occlusion, six with dissection, five with moyamoya disease, nine with other arteriopathies. Among these patients, those initially imaged with CTA were diagnosed more quickly than those with initial magnetic resonance imaging/angiography, which facilitated thrombectomy and thrombolytic therapy. Twenty out of 51 had AIS without arterial abnormalities on CTA or MRA: eight with lenticulostriate vasculopathy and 12 with other small-vessel AIS. Among these patients, 80% were ineligible for thrombolysis for reasons beyond delay to diagnosis, and all showed good outcomes with supportive treatments alone. INTERPRETATION: Clinical features at presentation influence rapidity with which childhood AIS is suspected and diagnosed. Readily available CTA can direct thrombectomy in patients with large vessel occlusion and thrombolysis in most, but not all, eligible patients. WHAT THIS PAPER ADDS: Children with acute ischaemic stroke (AIS) commonly present with symptoms other than sustained hemiparesis. Stroke is more slowly recognized in these patients, which limits potential therapies. Computed tomography angiography (CTA) accurately identifies AIS with large vessel occlusion, enabling timely endovascular thrombectomy. CTA is sufficient to direct thrombolytic therapy in most eligible children. Most childhood AIS without arterial abnormalities identified by CTA had good outcomes.

Return to the Emergency Department Within 3 Months Following Pediatric Acute Concussion.

OBJECTIVE: To determine the proportion of concussed children returning to the emergency department (ED) for a concussion-related reason within 3 months of initial presentation and to determine which clinical composite score (5P or Post-Concussion Symptom Inventory) best predicts a return visit. SETTING, DESIGN, AND PARTICIPANTS: We combined a secondary analysis of data from the prospectively collected 5P study with a retrospective medical record review of children aged 5 to 18 years who returned to the Children's Hospital of Eastern Ontario (CHEO) ED for a concussion-related reason within 3 months of an acutely diagnosed concussion. Among 770 eligible participants, 632 children (median age: 11.8 [interquartile range (IQR), 9.0-14.5] years; 58.9% male) were included in the study. MAIN MEASURES: The primary outcome was the number of patients who returned to CHEO ED for a concussion-related reason within 3 months of an acute concussion diagnosed at CHEO ED. The secondary outcome was number of patients who returned within 14 days. RESULTS: Forty-seven children (7.4%; 95% confidence interval [CI]: 5.6-9.7) had a concussion-related return to the ED within 3 months, the majority of which occurred in the first 14 days (29/47; 61.7%; 95% CI: 47.4-74.2). History of migraines (21.3% vs 9.7%; P = .03) were more common in those with a return visit. Headache was the most frequently reported symptom (87.2%) on revisit. Females aged 13 to 18 years had the highest return rate (survival rate: 85.8% [95% CI: 79.8-92.3]) compared with males and younger age groups. In multivariable Cox hazards regression modeling, inclusion of risk scores improved prognostication (pseudo R2 = 8%). The difference in pseudo R2 between 5P and Post-Concussion Symptom Inventory is small. CONCLUSION: Most children and adolescents do not return to the ED following an acute concussion. Female youth with medium to high 5P scores at the index concussion visit may benefit from early referral to interdisciplinary specialty concussion care to guide treatment in anticipation of prolonged symptoms. By identifying these risk factors at the initial ED visit, healthcare and patient burden may be reduced.

Image-guided abscess drainage in children with perforated appendicitis - can it wait?

BACKGROUND: Image-guided drainage is the management of choice for perforated appendicitis with intra-abdominal abscess/es. However, there is paucity of data regarding the optimal time for intervention in children. OBJECTIVE: The purpose of this study is to assess the relationship between the time from diagnosis of a drainable abscess to abscess drainage (delta time) and the clinical outcome in patients with complicated acute appendicitis. MATERIALS AND METHODS: This is an institutional review board (IRB)-approved retrospective study comprising 80 pediatric patients who had image-guided abscess drainage due to perforated acute appendicitis. Delta time was associated with clinical outcome including length of stay, catheter dwell time, need for additional interventions, and need for tissue plasminogen activator (t-PA). Gamma regression models were used to assess the adjusted effect of delta time on the "length of stay" and "catheter dwell time" using "volume of the largest abscess" and "number of collections" as severity indices. Logistic regression was used to assess the effect of delta time on the "need for the t-PA" and "need for additional interventions." RESULTS: Mean age (SD) was 10.2 (3.8) years. Mean time between diagnosis and intervention (delta time) was 1.5 (1.2) days. There was no evidence that delta time effects the length of stay, catheter dwell time, need for t-PA, and need for additional interventions (P > 0.05). However, there was an association between the number of collections and volume of the largest abscess with length of stay (P = 0.006; P = 0.058), catheter dwell time (P = 0.029; P < 0.001), and need for additional interventions (P = 0.029; P = 0.016). CONCLUSIONS: Our results suggest that time between diagnosis of an appendicitis associated abscess and intervention is not significantly associated with need for tPA, need for additional intervention, drain dwell time, or length of stay.